At first glance, the stories taking the top two spots in Science News’ review of 2016 have little in common. Scientists began searching decades ago for gravitational waves. Discussions of these subtle signals from dramatic and distant phenomena appear dozens of times in the SN archive starting as early as the 1950s. Their long-awaited discovery, our No. 1 story of the year, touched off celebration of a new era in astronomy.

Less expected, and far from subtle, was the sudden rise in Brazil of microcephaly cases, linked this year to Zika virus infections — our No. 2 story. Little was known about Zika before the outbreak, which delivered devastation and fear across the Americas. In fact, only a single previous mention of Zika exists in the SN archive, in a book review from the 1990s.

But the stories have at least one thing in common: Both highlight the power of scientific discoveries to trigger our deepest human emotions. Pure elation as well as overwhelming dread can accompany research advances.